Semiconductor memory devices, including flash memory, typically utilize memory cells to store data as an electrical value, such as an electrical charge or voltage. Flash memory is a non-volatile data storage device that can be electrically erased and reprogrammed. More generally, non-volatile memory (e.g., flash memory, as well as other types of non-volatile memory implemented using any of a variety of technologies) retains stored information even when not powered, as opposed to volatile memory, which requires power to maintain the stored information.
Data hardening, the saving of data and mission critical metadata held in volatile storage, is an integral part of a storage device. When there is a power failure, mission critical data may reside in volatile memory in a number of sub-system components. Coordinating and managing multiple sub-system components to ensure that volatile data is saved successfully is important for safeguarding data integrity of a storage device.
For this reason, many flash memory-based data storage devices, such as Solid-state Drives (SSDs), employ an energy storage system for supplying power during a power failure operation. Energy storage elements of these critical systems, however, typically degrade over time and also face the risk of unexpected failures, impacting their ability to hold sufficient charge for a power failure operation.